1. Field of the Invention
The invention relates to an apparatus for carrying and transporting loads comprising a supporting platform and an air cushion device. The air cushion devise comprises a flexible damping ring inflatable by the introduction of a pressure medium, fixed to the supporting platform along a circular closed loop line of contact in sealing relationship, and an uplift chamber formed between the supporting platform, the inflated damping ring and the area of support. The chamber of the damping ring comprises at least one aperture through which it communicates with the uplift chamber and from which, in the operational condition, the pressure medium emerges between the damping ring and the area of support to form a fluid film.
2. Prior Art
Apparatus typical of the prior art is shown in German accepted specification No. 19 48 304. Such apparatus requires virtually level, very smooth areas of support. In order to compensate for irregularities, minor cracks and other non-uniformities in the area of support, a large consumption of pressure medium, and thus of energy, is necessary because of the narrow annular sliding surface which is only a few millimeters wide, and which in the event of irregularities, causes the pressure medium to escape rapidly. Problems also arise if the pressure of the escaping pressure medium is subject to wide fluctuations such as may arise e.g. when passing from an even to an uneven or from a smooth to a rough or porous area of support. This may frequently result in undesirable cyclical hopping movements due to resonance vibrations of the apparatus. In addition, high frequency vibrations arise which are accompanied by noise pollution. During travelling over cracks and steps the resulting rapid escape of pressure medium may often result in tilting, i.e. the damping ring will then rest in firm contact on the area of support, and further movement may involve a risk of the ring being turned inwards, and then even being torn or ripped off the support platform, resulting in failure of the entire transport device.
A further disadvantage of the known apparatus resides in the low lifting level, for which reason it may be very difficult or impossible to move the apparatus underneath the loads. If relatively high pressures are employed, the walls of the damping ring must be constructed of a fluid-tight, very strong material of low elasticity. In this context, the bulk of the load has to be carried by the outer peripheral margin. If this margin is reinforced by endless metal rings, which prevent radial-deflection, high frequency noisy vibrations result even in the event of only slight alterations in pressure.